Wakesurfing boat

ABSTRACT

A wakesurfing boat for creating a wave suitable for surfing in the wake of the boat. A length to beam (L/B) ratio of 3.21 combined with a rounded hull bottom proximate the transom minimizes losses in the wake wave. Elliptical arcuate portions extending from starboard and port points on the transom to selected positions on the respective starboard and port bulwarks further minimize losses in the wake wave. The hull bottom defines an M-shaped portion and a V-shaped portion. A propulsion system includes an exhaust pipe projecting from the hull bottom below the waterline, with an exhaust opening forward of the transom. A propeller has a hub and at least three blades. A blade area, defined by a sum of the area of the blades, is larger than 70% of a disk area, defined by a sum of the hub and the blades.

BACKGROUND OF THE INVENTION

The present invention relates to a wakesurfing boat, having a hullconfiguration adapted to produce a relatively large, long-lasting, andwell-shaped wave in the wake of the boat, on which a wakesurfer can rideon a surf board, similar to surfing on a natural ocean wave.

DESCRIPTION OF THE PRIOR ART

Wakesurfing is a watersport that is rapidly growing in popularity. Awakesurfer, being towed behind a boat, while standing on a surf boardand holding onto a tow rope, rides on a wave created in the wake of theboat, similar, in some respects, to a waterskier or a wakeboarder.Ideally, the boat should generate, in its wake, a wave that as closelyas possible mimics a size, a shape of a face, a shape of a crest, and aduration, of an ocean wave. If the wake wave reaches a sufficient size,shape, and duration, the wakesurfer, unlike a waterskier or awakeboarder, can release the tow rope, and ride the surf board on thecrest and the face of the wake wave, traversing back and forth on thewake wave, similar to an ocean surfer.

Until now, wakesurfers have been attempting to surf primarily in thewakes of existing cruising boats, waterskiing boats, and wakeboardingboats. A problem with attempting to wakesurf behind such traditionalboats, however, is that such boats fail to generate sufficiently large,sufficiently well-shaped, and sufficiently long-lasting wake wavesnecessary to give the wakesurfer a long, satisfying ride. Traditionalboats also release engine exhaust gases into the air in the surfing areain the wake of the boat, causing discomfort to the wakesurfer.

As is known in the field of fluid dynamics, a boat, when passing througha body of water, creates separate waves that move in the boat's wake. Ingeneral, separate wake waves originate, respectively, from the boat'sbow, centerline, quarter, and stern. Each wake wave generally forms thearms of a V, with the source of the respective wake wave being at thepoint of the V (i.e., the boat), and transverse curled wave crestsforming offset from the path of the boat. Wake wave height is a functionof several factors, including for example, a speed of the boat on thesurface of the water, resistance to the boat as it moves through thewater, a shape of the bottom of the hull, a length of the hull, alength/beam (L/B) ratio of the hull, a speed/length ratio (SLR) of thehull, a Froude number (Fr) of the hull, an amount of the bottom of thehull in contact with the body of water, hull displacement, hull trim,and an efficiency of the boat's propeller at the relatively high loadsassociated with wake surfing.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a wakesurfing boatthat provides, in its wake, a relatively large, relatively long-lasting,and relatively well-shaped wake wave, mimicking as closely as possiblean ocean wave, in order to give a wakesurfer a long satisfying surfingexperience substantially similar to that of an ocean surfer.

It is another object of the present invention to provide a wakesurfingboat and a hull for a wakesurfing boat capable of operating in separatemodes, including a cruising mode, a static surfing mode, and a dynamicsurfing mode.

It is a further object of the invention to provide a wakesurfing boat,configured with a ballast system capable of moving ballast rapidly andefficiently, in order to change the trim and displacement of the boatrapidly and efficiently, to thereby rapidly and efficiently shift themodes of operation.

It is a further object of the present invention to provide a wakesurfingboat configured to maximize wave resistance to the boat and the hull, totransform the power from the engine, and to maximize the efficiency ofthe propeller, in order to generate as much wave power as possible.

It is a further object of the present invention to provide a wakesurfingboat configured to substantially prevent engine exhaust from beingreleased behind the first wave crest and entering the air in the surfingarea aft of the boat, thereby minimizing or preventing discomfort to thewakesurfer caused by the exhaust gases.

These and other objects of the present invention will be apparent fromreview of the following specification and the accompanying drawings.

In view of the above objectives of the invention, a wakesurfing boat asdepicted, disclosed, and claimed below, substantially obviates one ormore of the shortcomings of the related art.

A wakesurfing boat includes a hull, the hull having a bow, a stern, atransom positioned at the stern, a starboard bulwark, a port bulwark, alength L between the bow and the stern, a transom positioned at thestern, a beam B between the starboard and port bulwarks, a bottom, and acenterline CL extending between the bow and the stern.

The boat, moving through water, creates a wake with minimum losses whenthe hull has a L/B ratio of approximately 3.21 with a rounded portion onthe hull bottom proximate the transom. The rounded portion defines afillet between the hull bottom and the starboard and port bulwarksproximate starboard and port points on the transom. The rounded portionon the hull bottom has a maximum radius related to the beam B ofapproximately 0.04(B).

The hull also has starboard and port arcuate portions defined on thestarboard and port bulwarks, respectively, proximate the stern,extending outboard from the respective starboard and port points on thetransom forward to respective starboard and port positions on thestarboard and port bulwarks. The starboard and port arcuate portionseach extend forward a distance equal to approximately 0.3(L). Thestarboard and port arcuate portions define partial arcs of starboard andport ellipses, each ellipse defined by a major radius equal to 0.2(L) to0.4(L), preferably 0.3(L) and a minor radius equal to 0.2(B) to 0.3(B),preferably 0.24(B).

The respective starboard and port points on the transom are positionedspaced to starboard and port, respectively, of the CL. Each of thestarboard and port points is spaced from the centerline by a distanceequal to 0.26(B).

The bottom of the hull defines an M-shaped portion, a V-shaped portion,a generally flat portion where the M-shaped portion meets the V-shapedportion, and a rounded portion proximate the transom.

The M-shaped portion on the hull bottom extends from a positionproximate the bow aft to a position located intermediate the bow and thestern, i.e., amidships, and more specifically, 0.4(L) to 0.5(L),measured aft from the bow.

The V-shaped portion on the hull bottom extends from the transom to theamidships position, located approximately 0.4(L)-0.5(L) aft of the bow.At the transom, an angle α is defined by the V-shaped portion of 100.Angle α of the V-shaped portion decreases steadily to 7° at theamidships position where the hull bottom begins to transform into theM-shaped portion.

The wakesurfing boat further includes a ballast system and a propulsionsystem.

The propulsion system includes at least an engine and an exhaust pipewith an exhaust aperture. The exhaust pipe extends below the waterlineof the hull and is attached to a wing-shaped body having a full wingprofile between the bottom of the hull and the exhaust aperture. Theexhaust aperture, through which the engine exhaust gases are omitted, ispositioned forward of the transom. As a result of the above combinationof structural features, exhaust gases are emitted below the wake waveaft of the transom, not in the air of the surfing area aft of thetransom.

The propulsion system further includes a propeller. The propeller has apreselected disc area and a preselected blade area. The preselectedblade area is larger than the preselected disc area by approximately70%.

The boat's ballast system includes a plurality of ballast tanks, piping,and pumps for routing ballast water into the boat, between the ballasttanks, and overboard, as desired by a user of the boat. A controller,operated by a boat operator, controls operation of both the ballastsystem and the propulsion system. The controller enables the boatoperator to selectively change acceleration, speed, ballast, trim, anddisplacement, in order to operate the wakesurfing boat in differentmodes of operation, including at least a cruising mode, a static surfingmode, and a dynamic surfing mode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a wakesurfing boat in accordance with theinvention;

FIG. 2 is a top view of the wakesurfing boat in accordance with theinvention;

FIG. 3 is a front view of the wakesurfing boat in accordance with theinvention;

FIG. 4 is a rear top perspective view of the wakesurfing boat inaccordance with the invention;

FIG. 5 a is a starboard side profile view of the wakesurfing boat inaccordance with the invention, depicting locations along the length ofthe hull of spaced cross-sectional cuts A-O at preselected locationsbetween them stern and the bow, respectively;

FIG. 5 b is an upper plan view of the wakesurfing boat in accordancewith the invention, depicting the location of the spaced cross-sectionalcuts shown in FIG. 6;

FIG. 6 is a body plan view of the wakesurfing boat in accordance withthe invention, depicting the relative shape of each of thecross-sectional cuts A-O shown in FIGS. 5 a and 5 b;

FIG. 7 a is a front perspective view of a hull bottom in accordance withthe invention;

FIG. 7 b is an upper perspective view depicting stern details of a hullin accordance with the invention;

FIG. 8 is a graph depicting an optimum length to beam ratio LJB toobtain a large wave using the wakesurfing boat in accordance with theinvention;

FIG. 9 is a top view of the hull of the wakesurfing boat in accordancewith the invention, proximate the stern, depicting laterally-projectingarcuate portions extending between starboard and port endpoints on thetransom to respective starboard and port positions on the respectivestarboard and port bulwarks, configured to minimize losses fromturbulence and speed gradients in the wake, each arcuate portiondefining an arc of a respective ellipse;

FIG. 10 a is a side view of the stern of the wakesurfing boat inaccordance with the invention, depicting a rounded stern portionconnecting the hull bottom to the starboard bulwark and the transom;

FIG. 10 b is a side perspective view depicting the rounded stern portionof FIG. 10 a;

FIG. 11 is a top plan view depicting a preferred location of ballasttanks in the wakesurfing boat in accordance with the invention;

FIG. 12 a is a plan view depicting system details of ballast pipes andpumps, used with the ballast tanks depicted in FIG. 11 in thewakesurfing boat in accordance with the invention;

FIG. 12 b is a cross-sectional view of a ballast tank of FIG. 11,depicting a ballast filling and discharge principle for the ballasttank;

FIG. 13 is a top plan view depicting a portion of a propulsion system inthe wakesurfing boat in accordance with the invention, and aninteraction of the propulsion system, and the ballast system in thewakesurfing boat in accordance with the invention;

FIG. 14 a is a side view depicting the configuration of an exhaust pipein the wakesurfing boat in accordance with the invention, and thelocation of the exhaust pipe aperture in relation to the transom;

FIG. 14 b is a perspective view depicting the configuration of theexhaust pipe of FIG. 14 a;

FIG. 15 is a front view of a propeller used in the wakesurfing boat inaccordance with the invention;

FIG. 16 is a side view of a wakesurfing boat in accordance with theinvention, in a cruising mode;

FIG. 17 is a side view of a wakesurfing boat in accordance with theinvention, in a static surfing mode;

FIG. 18 is a side view of a wakesurfing boat in accordance with theinvention, in a dynamic surfing mode; and

FIG. 19 is a top view graphically depicting a wave in the wake of awakesurfing boat, in accordance with the invention, operating in adynamic surfing mode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Other embodiments of the invention will be apparent to those skilled inthe art from consideration of the specification and practice of theinvention disclosed herein. It is intended that the specification andexamples be considered as exemplary only, with a true scope and spiritof the invention being indicated by the attached claims.

In accordance with the invention, and as broadly embodied in FIGS. 1-7,a wakesurfing boat 10, in accordance with the present invention,includes a hull 20. The hull 20 includes a bow 22, a stern 24, a transom25 positioned at the stern, a starboard bulwark 26, a port bulwark 28, acenterline CL extending between the bow 22 and the stern 24 intermediatethe starboard and port bulwarks 26, 28, a length L between the bow 22and the stern 24, a beam B between the starboard bulwark 26 and the portbulwark 28, and a hull bottom 29. In one preferred embodiment, thelength L of the hull is 13.37 meters. In one preferred embodiment, themaximum beam B is 4.54 meters. The actual preferred length L and beam B,however, will be selected to achieve a preferred length to beam (LUB)ratio, as discussed below.

In accordance with the invention, and as embodied in FIGS. 3, 5 a, 5 b,6, and 7 a, an M-shaped portion 30 is defined on the hull bottom 29. TheM-shaped portion 30 includes a central vertex 32, defined by a keel lineof the hull, a starboard vertex 34, a port vertex 36, a starboard nadir37, and a port nadir 38. Referring to FIGS. 5 a and 5 b, the bottom 29of the hull 20 further includes a sheer line 132, first and second innerchines 134 and 136 on each of the starboard and port bulwarks,respectively (the chines on the starboard bulwark 26 are shown in FIG. 5a, and the chines on the port bulwark 28 are shown in FIG. 5 b). Anouter chine 138 is also defined on each bulwark. The starboard and portvertices 34 and 36 of the M-shaped portion 30 correspond to forwardportions of the first inner chines 136. Referring to FIG. 7 a, theM-shaped portion 30 extends from the bow 22, along the bottom 29 of thehull 20, to a position P1, substantially amidships on the bottom 29 ofthe hull 20, between 0.4(L), and 0.5 (L) measured aft from the bow. TheM-shaped portion 30 increases mass, and consequently increases efficientdisplacement, by trapping water and building up a bow wave between thestarboard vertex 34 and the port vertex 36. The starboard and portvertices 34 and 36 also divide flow of the surface water under thebottom 29 of the hull 20, and direct spray towards the center of thebottom 29, thereby minimizing spray on the bulwarks of the hull 20 inthe dynamic surfing mode M_(sd), thereby increasing the wave quality inthe wake, leaving a more clean surface flowing aft, and providing aclean surface area to the wake wave.

In accordance with the invention, and as embodied in FIGS. 6 and 7 a, aV-shaped portion 40 is defined on the bottom 29 of the hull 20,extending from the transom 25 to the amidships position P1 where thebottom transforms into the M-shaped portion 30. The V-shaped portion 40defines an angle α of 10° at the transom 25. Angle α decreases steadilyalong the length of the V-shaped portion 40 until it reaches an angle of7° at amidships position P1. The transition of the V-shaped portion 40to the M-shaped portion 30 at position P1 results in a section of thehull bottom which is relatively flat and nearly rectangular, aconfiguration which is beneficial for carrying an amount of ballastneeded when the boat operates in the dynamic surfing mode M_(sd). At theposition P1, the outer chine 138 transforms into a forward outer chineportion, and an aft outer chine portion. In addition, at position P1,the first inner chine 134 converts into a forward first inner chineportion, and an aft first inner chine portion. Likewise, at position P1,the second inner chine 136 transforms into a forward second inner chineportion, and an aft second inner chine portion. The starboard and portforward second inner chine portions correspond to the starboard and portvertices 34 and 36, respectively, of the M-shaped portion 30. Thecombination of these bow, stern, and mid-hull configurations contributesto the capability of the hull 20 to carry a large quantity of ballast,and a wake wave having relatively high quality, quantified in height,steepness, and smoothness of the wave crest and wave face. The 10° angleat the transom 25 also assists in the creation of a large surfing wave.

In accordance with the invention, the hull 20 includes a preferredlength to beam ratio L/B. As embodied in FIG. 8, a preferred L/B ratiois 2.9 to 3.65, preferably 3.1 to 3.3, and most preferably, inaccordance with the invention, 3.21. The optimum L/B ratio of 3.21, witha rounded hull bottom proximate the transom, results in a closed wakewave. The closed wake wave meets a “rooster tail” of the wake, producinga diverging wake wave, with wave components W1 and W2 on starboard andport sides of the boat, respectively, as shown in FIG. 19. This optimumL/B ratio, combined with the rounded hull bottom proximate the transom,also results in the wake wave having minimum losses.

As broadly embodied in FIGS. 5 a, 5 b, 7 b, 10 a, and 10 b, a roundedportion 200, between the aft portion of the first inner chine 134 andthe aft portion of the outer chine 138, is defined on the bottom 29 ofthe hull 20, proximate the transom 25, thereby defining a fillet betweenthe bottom 29 and the respective starboard and port bulwarks 26 and 28at starboard and port points 55 and 56 defined on the transom 25. Eachof the starboard and port points 55 and 56 on the transom 25 arelocated, respectively, spaced to starboard and port of the centerline CLby an amount equal to 0.26(B), defining a total distance between thetransom points 55 and 56 of 0.52(B). In a preferred embodiment, therounded portion 200, as depicted in FIG. 10 a, has a maximum radiusrelative to the beam B of 0.03(B) to 0.05(B), and most preferably0.04(B). In the presently preferred embodiment, this maximum radius of0.04(B) is equal to 154 mm. The rounded portion 200, combined with thepreferred L/B ratio of 3.21 minimizes losses due to turbulence in thewake wave.

To further minimize losses in the wake wave from turbulence and largespeed gradients, and in accordance with the invention, a portion of theaft hull body, proximate the stern 24, in a horizontal plane, isrounded, with the rounded aft hull body Intersecting the transom 25 andthe starboard and port bulwarks 26 and 28 of the hull 20. In accordancewith the invention, and as broadly embodied in FIG. 9, the hull 20includes starboard and port arcuate portions 52 and 54, extendingoutboard from the respective starboard and port points 55 and 56 on thetransom. The starboard and port arcuate portions 52 and 54 havegenerally partially-elliptical shapes each arcuate portion defining apartial arc of a respective starboard and port ellipse proximate thetransom 25, as depicted in FIG. 9, each of the ellipses being defined bya major radius equal to 0.2(L) to 0.4(L), preferably 0.3(L), and a minorradius equal to 0.2(B) to 0.3(B), preferably 0.24(B). The starboard andport arcuate portions 52 and 54 extend from the starboard and porttransom points 55 and 56, forward to respective starboard and portpositions 57 and 58 on the starboard and port bulwarks 26 and 28 of thehull 20. A preferred distance that the starboard and port arcuateportions 52 and 54, respectively, extend from the respective starboardand port transom points 55 and 56, to the respective starboard and portbulwark positions 57 and 58 is between 0.2(L)-0.4(L), preferably 0.3(L).The outboard rounding of the bulwarks 26 and 28 proximate the transom 25increases the amount that the hull 20 sinks during the dynamic surfingmode M_(sd), thereby increasing hull displacement and resultant wakewave height.

In accordance with the invention, and as broadly embodied in FIG. 11, aballast system 60 preferably includes six (6) ballast tanks, including afirst ballast tank 62, a second ballast tank 64, a third ballast tank65, a fourth ballast tank 66, a fifth ballast tank 67, and a sixthballast tank 68, positioned at alternating positions above the hullbottom 29, adjacent the starboard and port bulwarks 26 and 28, betweenthe stern 24 and the bow 22. FIG. 10 also depicts the position of thecenter of buoyancy CB of the hull 20. Preferably, the first ballast tank62 has a total capacity of 2,549 liters, a longitudinal center ofgravity (LCG) of 1.81 meters, a vertical center of gravity (VCG) of 0.59meters, and a transverse center of gravity (TCG) of 1.59 meters.Preferably, the second ballast tank 64 has a total capacity of 2,549liters, an LCG of 1.81 meters, a VCG of 0.59 meters, and a TCG of −1.59meters. Preferably, the third ballast tank 65 has a total capacity of2,910 liters, an LCG of 7.65 meters, a VCG of 0.69 meters, and a TCG of1.63 meters. Preferably, the fourth ballast tank 66 has a total capacityof 2,910 liters, an LCG of 7.65 meters, a VCG of 0.69 meters, and a TCGof −1.63 meters. Preferably, the fifth ballast tank 67 has a totalcapacity of 1,975 liters, an LCG of 10.72 meters, a VCG of 0.87 meters,and a TCG of 0.79 meters. Preferably, the sixth ballast tank 68 has atotal capacity of 1,975 liters, an LCG of 10.72 meters, a VCG of 0.87meters, and a TCG of −0.79 meters.

As further broadly embodied in FIGS. 1 a and 1 b, the ballast system 60includes a ballast tank piping and pumping system 70. The ballast tankpiping and pumping system 70 includes a plurality of ballast tankfilling pipes 72, a plurality of ballast tank discharge pipes 74, andoverflow vent pipes 77, with each of the various pipes 72, 74, 75, and77 being associated with respective ballast tanks. In addition, theballast tank piping, pumping, and control system 70 includes associatedflow regulation valves, throttle valves, choke valves, and gate valves76, ballast water pumps 78, and a controller 79. The controller 79enables the operator of the wakesurfing boat 10 to manually orautomatically control operation of the pumps 78 and valves 76, in orderto selectively fill and drain various ballast tanks as desired. Theconfiguration, and the principles of operation, of theautomatically-controlled ballast piping and pumping system 70 areconventional, and known to persons of ordinary skill in the art, andtherefore will not be further discussed here.

In accordance with the invention, and as broadly embodied in FIGS.12-13, a propulsion system 80 includes starboard and port engines 82 and84, an engine exhaust discharge pipe 90, a propeller shaft (not shown),and a propeller 100. The controller 79, operated by the boat operator,in addition to controlling the ballast tank piping and pumping system70, also controls the main engines 82 and 84 to regulate the speed ofthe wakesurfing boat 10. The speed of the wakesurfing boat 10, incombination with the ballast tank load, and the resultant trim anddisplacement of the wakesurfing boat 10, results in an ability tooperate the boat 10 in different modes of operation, as explained below.

In accordance with the invention, and as broadly embodied in FIG. 12,the engine exhaust discharge pipe 90 extends from the transom 25 belowthe hull bottom 29 and offset from the centerline CL, with an exhaustopening 92 being defined in the exhaust pipe 100 mm forward of thetransom 25. The exhaust from the engines 82 and 84, as a result, isreleased submerged in the water, and is carried aft in the wake wave aftof the hull 20, rather than being released and carried aft in the airaft of the hull 20. It is preferred that at least one wing-shapedportion 92 be attached to the exhaust pipe 90 between the exhaust pipe90 and the hull bottom 29. The at least one wing-shaped portion 92preferably has a portion with a height of approximately 120-150 mm, anda length approximately 4-5 times an outer diameter of the exhaustopening 92. The above-described combination of structural featuresresults in the wake wave closing above the exhaust gasses, thereby notallowing the exhaust gases to exit the water into the air in the wake ofthe boat 10, and hence avoiding discomfort to the wakesurfer.

In accordance with the invention, and as broadly embodied in FIG. 15,the propulsion system 80 includes a propeller 100. The propeller 100includes a hub and at least three propeller blades 104. The hub and theblades define a disk 102. The disk 102 defines a first circle C₁ havinga first diameter D₁, and a first area A₁=(π/4) D₁ ² The total area ofthe blades 104 defined by the projected blade area on the surface of thedisc 102, defines a second area A2. Propulsion in the dynamic surfingmode M_(sd) (discussed below) requires high efficiency at high load onthe propeller. In the dynamic surfing mode M_(sd), the propeller 100needs to propel the boat 10 up to an optimum surfing speed. Thisrequires a large thrust at a relatively low speed, thereby placing ahigh load on the blades 104. Transmission of maximum thrust and power tothe water requires a large blade area. In addition, if the blade area istoo small, the water is unable to carry the load and will start tocavitate in the wake, reducing propeller efficiency and thrust.Wakesurfing boat 10, in accordance with the invention, operating in thedynamic surfing mode M_(sd), with a large amount of ballast, enjoysmaximum thrust and propeller efficiency because the second area A2,defined by a sum of the area of the projected area of the blades 104, islarger than 70% of the first area A₁ of the first circle C₁ defined bythe disc 102. Use of a ducted propeller as the propeller 100 also iscontemplated and within the scope of the invention.

As embodied in FIGS. 16-19, interaction of the ballast system and thepropulsion system, with resultant changes in ballast volume, ballastweight, and boat displacement and trim, results in at least threedifferent modes of operation for the wakesurfing boat 10, i.e., acruising mode M_(c) (FIG. 16), with the ballast tanks empty, and theboat 10 being propelled through the surface water; a static surfing modeM_(ss) (FIG. 17), with the ballast tanks in the process of filling, orfull, and the boat 10 sitting static in the surface water; and thedynamic surfing mode M_(sd) (FIG. 18), with the ballast tanks full, andthe boat 10 being propelled through the surface water. In the dynamicsurfing mode M_(sd), as a result of the greater hull displacement,greater propeller thrust, greater propeller efficiency, optimized L/Bratio, and minimized losses in the wake resulting from the rounded afthull bottom and the rounded aft body hull, intersecting with the transomand the bulwarks, a wake wave is created with an improved height,steepness, crest smoothness, face smoothness, and duration, all of whichare very desirable for surfing. FIG. 19 graphically depicts a wave inthe wake of the above-described preferred embodiment of the wakesurfingboat 10, in accordance with the invention, including a starboard wavecomponent W1 and a port wave component W2, created by the wakesurfingboat 10 operating in the dynamic surfing mode M_(sd). Each of the wakewave components W1 and W2 defines a relatively large, relativelylong-lasting, and relatively well-shaped wake wave, mimicking as closelyas possible an ocean wave, thereby providing the wakesurfer a longsatisfying surfing experience substantially similar to that of an oceansurfer.

What is claimed is:
 1. A wakesurfing boat comprising: a hull, the hullcomprising: a bow; a stern; a starboard bulwark; a port bulwark; atransom positioned at the stern, the transom having starboard and portpoints between the starboard and port bulwarks; a length L between thebow and the stern; a beam B between the starboard and port bulwarks abottom; a deck; a centerline extending between the bow and the sternmidway between the port and starboard bulwarks; a rounded aft hull bodyintersecting the transom, the starboard bulwark, and the port bulwark,the rounded aft hull body including: a starboard arcuate portionextending outboard from the starboard bulwark proximate the stern, thestarboard arcuate portion connecting the starboard point of the transomto a position on the starboard bulwark intermediate the starboard pointon the transom and the bow, the starboard arcuate portion defining apartial arc of a starboard ellipse, the starboard ellipse defined on thedeck at the starboard side of the hull proximate the stern, thestarboard ellipse having a starboard major radius, the starboard majorradius being equal to approximately 0.2 (L) to 0.4(L), and a starboardminor radius, the starboard minor radius being equal to approximately0.2(B) to 0.3(B); and a port arcuate portion extending outboard from theport bulwark proximate the stern, the port arcuate portion connectingthe port point of the transom to a position on the port bulwarkintermediate the port point on the transom and the bow, the port arcuateportion defining a partial arc of a ort ellipse, the port ellipsedefined on the deck at the port side of the hull proximate the stern,the port ellipse having a port major radius, the port major radius beingequal to approximately 0.2(L) to 0.4(L), and a port minor radius, theport minor radius being equal to approximately 0.2(B) to 0.3(B); whereinthe starboard arcuate portion and the port arcuate portion intersect thestarboard and port points on the transom, respectively to define a widthbetween the starboard point of the transom and the port arc of thetransom which is less than the beam B; and wherein the starboard partialarc of the starboard ellipse defining the starboard arcuate portion andthe port partial arc of the port ellipse defining the port arcuateportion, thereby defining the rounded aft hull body, are configured tominimize losses in a wake wave; a ballast system; and a propulsionsystem.
 2. The wakesurfing boat of claim 1, wherein the major radius ofeach of the starboard ellipse and port ellipse is equal to 0.3(L), andthe minor radius of each of the starboard ellipse and the port ellipseis equal to 0.24(B).
 3. The wakesurfing boat of claim 1, furthercomprising a L/B ratio of approximately 3.1 to 3.3.
 4. The wakesurfingboat of claim 3, wherein the L/B ratio is equal to 3.21.
 5. Thewakesurfing boat of claim 1, wherein the bottom comprises a substantialM-shaped portion and a substantial V-shaped portion.
 6. The wakesurfingboat of claim 1, wherein a length of each of the respective starboardand port positions on the respective starboard and port bulwarks,measured from the respective starboard and port points on the transom,is approximately 0.3(L).
 7. The wakesurfing boat of claim 1, wherein therespective starboard and port points on the transom are located atrespective starboard and port sides of the centerline, spaced away fromthe centerline by a distance equal to approximately 0.26(B).
 8. Thewakesurfing boat of claim 5, wherein the substantial M-shaped portionextends along the bottom of the hull from a first position proximate thebow to a second position located approximately 0.4(L) to approximately0.5(L) aft of the bow.
 9. The wakesurfing boat of claim 8, wherein thesubstantial V-shaped portion extends from the transom to approximatelythe second position.
 10. The wakesurfing boat of claim 8, wherein thesubstantial V-shaped portion defines an angle of approximately 10° atthe stern, the angle decreasing to approximately 7° at the secondposition.
 11. The wakesurfing boat of claim 1, wherein the propulsionsystem comprises at least an engine, an engine exhaust pipe with anexhaust opening, and a propeller.
 12. The wakesurfing boat of claim 11,wherein the exhaust pipe is attached to a wing-shaped body dependingfrom the bottom and submerged below the transom.
 13. The wakesurfingboat of claim 12, wherein the exhaust opening is defined in the exhaustpipe forward of the transom.
 14. The wakesurfing boat of claim 12,wherein the wing-shaped body has a length approximately 4.0 to 5.0 timesgreater than a diameter of the exhaust opening.
 15. The wakesurfing boatof claim 11, wherein the propeller has a preselected blade area, and apreselected disc area, the preselected blade area being larger than 70%of the preselected disc area.
 16. The wakesurfing boat of claim 1,wherein the ballast system comprises a plurality of ballast tanksadapted to hold selected amounts of ballast water, a plurality of pipes,pumps, and valves adapted to transfer the ballast water inboard andoverboard.
 17. The wakesurfing boat of claim 16, further comprising acontroller for controlling operation of the ballast system and thepropulsion system, adapted to operate the boat in at least one of acruising mode, a static surfing mode, and a dynamic surfing mode. 18.The wakesurfing boat of claim 1, further comprising a rounded portion onthe bottom proximate the transom, the rounded portion having a maximumradius related to the beam B, and defining a fillet between the bottomand the starboard and port bulwarks proximate the starboard and portpoints on the transom.
 19. The wakesurfing boat of claim 18, wherein amaximum radius of the rounded portion on the bottom related to the beamB is 0.03(B) to 0.05 (B).
 20. The wakesurfing boat of claim 19, whereinthe maximum radius of the rounded portion on the bottom related to thebeam is 0.04(B).
 21. The wakesurfing boat of claim 1, wherein the widthbetween the starboard point on the transom and the port point on thetransom is approximately 0.52(B).